Breathing difficulty while lying down is an abnormal condition in which a person must keep the head elevated (by sitting or standing) to be able to breathe deeply or comfortably. The condition may also cause a person to wake up suddenly during the night feeling short of breath (paroxysmal nocturnal dyspnea).

This is a common complaint in people with some types of heart or lung problems. Sometimes the problem is subtle. People may only notice it when they realize that sleep is more comfortable with lots of pillows under their head, or their head in a propped-up position.